The objective is to conduct an integrated, multidisciplinary inquiry into the psychophysiology of cardiovascular reactivity. Our goal is to use psychophysiological, neurobiological, and behavioral methods to study cardiovascular regulatory processes, relationships between behavior and chronic disorders, and the development of efficacious treatments. The Project consists of four major areas, together with Core facilities supporting the program with biochemical urinary and plasma assays, computation/instrumentation, and psychophysiological data collection. The Cores contribute substantially to the implementation of each Project by using common methodological approaches. Project 1 will examine why black Americans have double the prevalence of hypertension as whites. The manner in which biobehavioral and psychosocial factors influence cardiovascular adjustments and neuroregulatory processes as a function of sex, race, and blood pressure level (normotension vs. borderline hypertension) will be examined during psychophysiological reactivity tasks in the laboratory and during ambulatory heart rate, blood pressure, and hormonal monitoring in natural settings. Project 2 will examine in mild or moderate hypertensives how beta blockers differing in selectivity, lipophilicity, and intrinsic sympathetic activity influence as a function of race and sex: (a) hemodynamic and hormonal reactivity to standardized behavioral challenges in the laboratory; (b) heart rate, blood pressure, and hormonal activity during ambulatory monitoring, (c) cognitive performance, (d) mood, and (e) fatigue. Project 3 will use psychophysiological reactivity tasks, autonomic function tests, and ambulatory monitoring in Type 1 diabetics to investigate: (a) interrelationships among autonomic function, glycemia, cardiovascular and neurohormonal reactivity, and behavior; (b) putative pathophysiological mechanisms responsible for autonomic neuropathy; (c) influences of psychosocial stressors and personality factors on pharmacologic, and/or behavioral interventions designed to exert glycemic control and moderate autonomic reactivity; and (d) influences of anti-hypertensive therapies upon glycemia, autonomic function, reactivity, and behavior. Project 4 will examine in rabbits, the CNS mechanisms underlying cardiovascular reactivity, and will assess the degree to which sympathetic nervous system induced reactivity is attenuated by behavioral conditioning or direct activation of sympathoinhibitory CNS pathways.